TY - JOUR TI - Occurrence and precipitation mechanism of silver in pyrite from chimney fragments in the Edmond hydrothermal field, Central Indian Ridge AU - Zhang, Huichao AU - Chen, Kean AU - Tao, Chunhui AU - Alveirinho Dias, Ágata AU - Liang, Jin AU - Yang, Weifang AU - Liao, Shili AU - An, Fang AU - Yin, Bohao AU - Sun, Chuanqiang T2 - Ore Geology Reviews DA - 2023/05// PY - 2023 DO - 10.1016/j.oregeorev.2023.105471 DP - DOI.org (Crossref) SP - 105471 J2 - Ore Geology Reviews LA - en SN - 01691368 UR - https://linkinghub.elsevier.com/retrieve/pii/S0169136823001865 Y2 - 2023/05/10/03:57:57 ER - TY - JOUR TI - Resource estimation of the sulfide-rich deposits of the Yuhuang-1 hydrothermal field on the ultraslow-spreading Southwest Indian Ridge AU - Yu, Junyu AU - Tao, Chunhui AU - Liao, Shili AU - Dias, Ágata AU - Liang, Jin AU - Yang, Weifang AU - Zhu, Chuanwei T2 - Ore Geology Reviews AB - Seafloor massive sulfide (SMS) deposits are important deep-sea mineral resources expected to occur predominantly on slow- and ultraslow-spreading mid-ocean ridges. Resource estimates are already available for some of the largest SMS deposits on slow-spreading ridges but not on ultraslow-spreading ridges. Based on geological mapping and sampling, this study investigates the distribution and content of sulfide-rich deposits in the Yuhuang-1 hydrothermal field (YHF), located on the ultraslow-spreading Southwest Indian Ridge. The sulfide-rich deposits in the YHF are composed of two areas ∼500 m apart: the southwest sulfide area (SWS) and the northeast sulfide area (NES). We calculated the volume of sulfide-rich mounds in the YHF and arrived at a total accumulation of ∼10.6 × 106 tons, including at least ∼7.5 × 105 tons of copper and zinc and ∼18 tons of gold. Furthermore, considering the coverage of layered hydrothermal sediment mixed with sulfide-rich breccias, which may have underlying massive sulfide deposits, the maximum total mass was estimated at ∼45.1 × 106 tons. This suggests that the YHF is one of the largest SMS deposits worldwide and confirm that ultraslow-spreading ridges have the greatest potential to form large-scale SMS deposits. DA - 2021/04/17/ PY - 2021 DO - 10.1016/j.oregeorev.2021.104169 SP - 104169 J2 - Ore Geology Reviews LA - en SN - 0169-1368 UR - https://www.sciencedirect.com/science/article/pii/S0169136821001943 Y2 - 2021/04/21/03:36:30 KW - Resource estimate KW - Seafloor massive sulfide deposits KW - Southwest Indian Ridge KW - Yuhuang-1 hydrothermal field ER - TY - JOUR TI - Geochemistry, sulfur and lead isotopic composition of hydrothermal sulfide from the Duanqiao hydrothermal field on the Southwest Indian Ridge: implications for ore genesis AU - Yang, Weifang AU - Liao, Shili AU - Alveirinho Dias, Ágata AU - Liang, Jin AU - Li, Wei AU - Ding, Teng AU - Tao, Chunhui T2 - International Geology Review AB - Hydrothermal activities on ultraslow-spreading ridges exhibit diverse characteristics, long histories with multiple participants, and might form large-scale, high-grade sulfide deposits. The Duanqiao hydrothermal field (DHF) is located at the segment with the thickest oceanic crust and a large axial magma chamber on the Southwest Indian Ridge, providing unique perspective of sulfide metallogenesis on ultraslow-spreading ridges. Previous studies revealed that DHF sulfide exhibits distinct features of enrichment of ore-forming elements in comparison with those of hydrothermal fields on sediment-starved mid-ocean ridges. However, the genesis and processes responsible for such differences remain poorly constrained. In this study, mineralogical, geochemical and S and Pb isotopic analyses were performed on relict sulfide mound samples to characterize DHF formation. The samples show clear concentric mineral zonation from the interior to the exterior wall. Assemblages of chalcopyrite, sphalerite, and pyrite are distributed mainly in the interior wall, whereas pyrite and marcasite are distributed mainly in the exterior wall. The low Cu content and Pb isotopic composition of the sulfide indicate that the metals are derived mainly from basement basalts. The δ34S values exhibit positive values distributed over a reasonably narrow range (2.42‰–7.97‰), which suggests approximately 62.1%–88.5% of S with basaltic origin. Compared with most hydrothermal fields along the sediment starved mid-ocean ridges, the DHF sulfide shows particularly high contents of Pb (263–2630 ppm), As (234–726 ppm), Sb (7.32–44.3 ppm), and Ag (35.2 to >100 ppm). The δ34S values exhibit an increasing tendency from the sample exterior to the interior. We propose that these features probably reflect the existence of a subsurface zone refining process. Our results provide new insight into the sulfide formation process and contribute to understanding the metallogenic mechanism of hydrothermal sulfides on ultraslow-spreading ridges. DA - 2022/05/31/ PY - 2022 DO - 10.1080/00206814.2022.2081937 DP - Taylor and Francis+NEJM VL - 0 IS - 0 SP - 1 EP - 17 SN - 0020-6814 ST - Geochemistry, sulfur and lead isotopic composition of hydrothermal sulfide from the Duanqiao hydrothermal field on the Southwest Indian Ridge UR - https://doi.org/10.1080/00206814.2022.2081937 Y2 - 2022/09/21/13:41:13 KW - Hydrothermal sulfide KW - geochemistry KW - southwest Indian ridge KW - sulfur isotope KW - zone refining ER - TY - CONF TI - Replacement or plume fallout? Both, please! Evidence from active and fossil VMS systems AU - Relvas, J M R S AU - Barriga, F AU - Pinto, A AU - Marques, A F AU - Carvalho, J AU - Dias, A Á T2 - 16th SGA Biennial Meeting 2022 C1 - New Zeland C3 - The critical role of minerals in the carbon-neutral future DA - 2022/// PY - 2022 ER - TY - JOUR TI - Evidence for mixed contribution of mantle and lower and upper crust to the genesis of Jurassic I-type granites from Macao, SE China AU - Quelhas, Pedro AU - Mata, João AU - Dias, Ágata T2 - GSA Bulletin AB - Abstract Much controversy has occurred in the past few decades regarding the nature of the sources, the petrogenetic processes, and the tectonic regime(s) of the Jurassic magmatism within the Southeast China magmatic belt. This study aims to contribute to the discussion with mineral chemistry, and whole-rock element and Sr-Nd-Hf-Pb isotopic geochemical data from granitic rocks and microgranular mafic enclaves from Macao, where two discrete groups of I-type biotite granites have been identified (referred to as Macao Group I [MGI] and Macao Group II [MGII]). It is proposed that the granitic magmas were generated by partial melting of infracrustal medium- to high-K, basaltic Paleoproterozoic to Mesoproterozoic protoliths (Nd depleted mantle model age [TDM2] = 1.7–1.6 Ga and Hf TDM2 = 1.8–1.6 Ga), triggered by underplating of hot mantle-derived magmas in an extensional setting related to the foundering of a previously flat slab (paleo–Pacific plate) beneath the SE China continent. The main differences between the two groups of Macao granites are attributed to assimilation and fractional crystallization processes, during which upper-crustal Paleozoic metasediments were variably assimilated by MGI magmas. This is evidenced by an increase in initial 87Sr/86Sr ratios with degree of evolution, presence of metasedimentary enclaves, and high percentage of zircon xenocrysts with Paleozoic ages. In addition, other processes like late-stage fluid/melt interaction and magma mixing also left some imprints on granite compositions (rare earth element tetrad effect plus non–charge-and-radius-controlled behavior of trace elements and decoupling between different isotope systems, respectively). The distribution of isotopically distinct granites in SE China reflects the nature of the two Cathaysia crustal blocks juxtaposed along the Zhenghe-Dapu fault. DA - 2021/01/01/ PY - 2021 DO - 10.1130/B35552.1 DP - DOI.org (Crossref) VL - 133 IS - 1-2 SP - 37 EP - 56 LA - en SN - 0016-7606, 1943-2674 UR - https://pubs.geoscienceworld.org/gsa/gsabulletin/article/133/1-2/37/584581/Evidence-for-mixed-contribution-of-mantle-and Y2 - 2021/03/30/07:27:27 ER - TY - JOUR TI - Magmatic Evolution of Garnet-Bearing Highly Fractionated Granitic Rocks from Macao, Southeast China: Implications for Granite-Related Mineralization Processes AU - Quelhas, Pedro AU - Mata, João AU - Dias, Ágata T2 - Journal of Earth Science AB - The widespread W-(Mo)-Sn-Nb-Ta polymetallic mineralization in Southeast (SE) China is genetically associated with Mesozoic highly fractionated granitic rocks. Such rocks have enigmatic mineralogical and geochemical features, making its petrogenesis an intensely debated topic. To better understand the underlying magma evolution processes, petrography, garnet chemistry and whole-rock major and trace element data are reported for Jurassic highly fractionated granitic rocks and associated microgranite and aplitepegmatite dikes from Macao and compared with coeval similar granitic rocks from nearby areas in SE China. Despite the fact that the most evolved rocks in Macao are garnet-bearing aplite-pegmatite dikes, the existence of coeval two-mica and garnet-bearing biotite and muscovite granites displaying more evolved compositions (e.g, lower Zr/Hf ratios) indicates that the differentiation sequence reached higher degrees of fractionation at a regional scale. Although crystal fractionation played an important role, late-stage fluid/melt interactions, involving F-rich fluids, imparted specific geochemical characteristics to Macao and SE China highly fractionated granitic rocks such as the non-CHARAC (CHArge-and-RAdius-Controlled) behavior of trace elements, leading, for example, to non-chondritic Zr/Hf ratios, Rare Earth Elements (REE) tetrad effects and Nb-Ta enrichment and fractionation. Such process contributed to the late-stage crystallization of accessory phases only found in these highly evolved facies. Among the latter, two populations of garnet were identified in MGI (Macao Group I) highly fractionated granitic rocks: small grossular-poor euhedral grains and large grossular-rich skeletal garnet grains with quartz inclusions. The first group was mainly formed through precipitation from highly evolved Mn-rich slightly peraluminous melts under low-pressure and relatively low temperature (∼700 °C) conditions. Assimilation of upper crust metasedimentary materials may have contributed as a source of Mn and Al to the formation of garnet. The second group has a metasomatic origin related to the interaction of magmatic fluids with previously crystallized mineral phases and, possibly, with assimilated metasedimentary enclaves or surrounding metasedimentary strata. The highly fractionated granitic rocks in Macao represent the first stage in the development of granite-related W-(Mo)-Sn-Nb-Ta mineralization associated with coeval more evolved lithotypes in SE China. DA - 2021/// PY - 2021 DO - 10.1007/s12583-020-1389-4 DP - Springer Link J2 - J. Earth Sci. LA - en SN - 1867-111X ST - Magmatic Evolution of Garnet-Bearing Highly Fractionated Granitic Rocks from Macao, Southeast China UR - https://doi.org/10.1007/s12583-020-1389-4 Y2 - 2021/04/10/08:37:01 ER - TY - JOUR TI - High-precision geochronology of Mesozoic magmatism in Macao, Southeast China: Evidence for multistage granite emplacement AU - Quelhas, Pedro AU - Dias, Ágata AU - Mata, João AU - Davis, Donald Wayne AU - Ribeiro, Maria Luísa T2 - Geoscience Frontiers DA - 2020/01// PY - 2020 DO - 10.1016/j.gsf.2019.04.011 VL - 11 IS - 1 SP - 243 EP - 263 J2 - Geoscience Frontiers LA - en SN - 16749871 ST - High-precision geochronology of Mesozoic magmatism in Macao, Southeast China UR - https://linkinghub.elsevier.com/retrieve/pii/S1674987119301033 Y2 - 2021/03/30/07:30:21 ER - TY - JOUR TI - Geology of the Macao Special Administrative Region (China) AU - Quelhas, Pedro AU - Borges, Ricardo AU - Dias, Ágata Alveirinho AU - Ribeiro, Maria Luísa AU - Costa, Pedro AU - Mata, João T2 - Journal of Maps AB - A 1:12,000 geological map of the Macao Special Administrative Region has been produced through detailed field work supported by petrographic, mineralogical, geochronological and geochemical data obtained in previous studies. This map aims to represent a reliable tool to understand the geological evolution of the region and for management of the territory. The geology of Macao is dominated by two groups of Jurassic granitic rocks belonging to an intrusive suite located along the coast of Southeast China: Macao Group I (MGI: 164.5 ± 0.6 to 162.9 ± 0.7 Ma) and Macao Group II (MGII: 156.6 ± 0.2 to 155.5 ± 0.8 Ma), including the associated microgranite, aplite and pegmatite dikes and quartz veins. Remnants of the metasedimentary wall-rock are present as Devonian xenoliths enclosed within the granites. Younger Jurassic to Cretaceous andesite to dacite dikes (150.6 ± 0.6 to <120 Ma) intrude the granitic rocks. Additionally, Quaternary sedimentary deposits cover the older lithologies. DA - 2021/// PY - 2021 DO - 10.1080/17445647.2021.1906340 DP - Taylor and Francis+NEJM VL - 0 IS - 0 SP - 1 EP - 11 SN - null UR - https://doi.org/10.1080/17445647.2021.1906340 Y2 - 2021/04/07/09:46:37 KW - Jurassic KW - Macao (South China) KW - Mesozoic KW - geological map KW - granites KW - magmatic rocks ER - TY - JOUR TI - Geological Map of the Macao Special Administrative Region (China) AU - Quelhas, P AU - Borgens, R AU - Dias, Ágata AU - Ribeiro, L AU - Costa, P AU - Mata, J T2 - Journal of Maps DA - 2021/// PY - 2021 DO - https://doi.org/10.1080/17445647.2021.1906340 ER - TY - JOUR TI - Material Source of Sediments from West Clarion–Clipperton Zone (Pacific): Evidence from Rare Earth Element Geochemistry and Clay Minerals Compositions AU - Qiu, Zhongrong AU - Tao, Chunhui AU - Ma, Weilin AU - Dias, Ágata Alveirinho AU - Hu, Siyi AU - Shao, Yuexiao AU - Yang, Kehong AU - Zhang, Weiyan T2 - Journal of Marine Science and Engineering AB - The geochemistry and mineralogy of sediments provide relevant information for the understanding of the origin and metallogenic mechanism of ferromanganese nodules and crusts. At present, there are still few studies on the sediment origin of the Clarion–Clipperton Zone (CCZ) of the east Pacific, particularly on the systematic origin of sediments with a longer history/length. Here, bulk sediment geochemistry and clay mineral compositions were analyzed on a 5.7 m gravity core (GC04) obtained at the CCZ, an area rich in polymetallic nodules. The results indicate that the average total content of rare earth elements (REE), including yttrium (REY), in sediments is 454.7 ppm and the REEs distribution patterns normalized by the North American Shale Composite of samples are highly consistent, with all showing negative Ce anomalies and more obvious enrichment in heavy REE (HREE) than that of light REE (LREE). Montmorillonite/illite ratio, discriminant functions and smear slide identification indicate multiple origins for the material, and are strongly influenced by contributions from marine biomass, while terrestrial materials, seamount basalts and their alteration products and authigenic source also make certain contributions. The REY characteristics of the sediments in the study area are different from those of marginal oceanic and back-arc basins, and more similar to pelagic deep-sea sediments. Based on LREE/HREE-1/δCe and LREE/HREE-Y/Ho diagrams, we conclude that samples from the study area had pelagic sedimentary properties which suffered from a strong “seawater effect”. DA - 2022/08// PY - 2022 DO - 10.3390/jmse10081052 DP - www.mdpi.com VL - 10 IS - 8 SP - 1052 LA - en SN - 2077-1312 ST - Material Source of Sediments from West Clarion–Clipperton Zone (Pacific) UR - https://www.mdpi.com/2077-1312/10/8/1052 Y2 - 2022/09/21/13:41:06 KW - Clarion–Clipperton Zone KW - material source KW - rare earth elements KW - sediments geochemistry ER - TY - JOUR TI - XRD Identification of Ore Minerals during Cruises: Refinement of Extraction Procedure with Sodium Acetate Buffer AU - Milinovic, Jelena AU - Dias, Ágata AU - Janeiro, Ana I. AU - Pereira, Manuel F. C. AU - Martins, Sofia AU - Petersen, Sven AU - Barriga, Fernando J. A. S. T2 - Minerals AB - The on-board identification of ore minerals during a cruise is often postponed until long after the cruise is over. During the M127 cruise, 21 cores with deep-seafloor sediments were recovered in the Trans-Atlantic Geotraverse (TAG) field along the Mid Atlantic Ridge (MAR). Sediments were analyzed on-board for physicochemical properties such as lightness (L*), pH and Eh. Selected samples were studied for mineral composition by X-ray powder diffraction (XRD). Based on XRD data, sediment samples were separated into high-, low- and non-carbonated. Removal of carbonates is a common technique in mineralogical studies in which HCl is used as the extraction agent. In the present study, sequential extraction was performed with sodium acetate buffer (pH 5.0) to remove carbonates. The ratio between the highest calcite XRD reflection in the original samples (Iorig) vs its XRD-reflection in samples after their treatment with the buffer (Itreat) was used as a quantitative parameter of calcite removal, as well as to identify minor minerals in carbonated samples (when Iorig/Itreat > 24). It was found that the lightness parameter (L*) showed a positive correlation with calcite XRD reflection in selected TAG samples, and this could be applied to the preliminary on-board determination of extraction steps with acetate buffer (pH 5.0) in carbonated sediment samples. The most abundant minerals detected in carbonated samples were quartz and Al- and Fe-rich clays. Other silicates were also detected (e.g., calcic plagioclase, montmorillonite, nontronite). In non-carbonated samples, Fe oxides and hydroxides (goethite and hematite, respectively) were detected. Pyrite was the dominant hydrothermal mineral and Cu sulfides (chalcopyrite, covellite) and hydrothermal Mn oxides (birnessite and todorokite) were mineral phases identified in few samples, whereas paratacamite was detected in the top 20 cm of the core. The present study demonstrates that portable XRD analysis makes it possible to characterize mineralogy at cored sites, in particular in both low- and high-carbonated samples, before the end of most cruises, thus enabling the quick modification of exploration strategies in light of new information as it becomes available in near-real time. DA - 2020/02/12/ PY - 2020 DO - 10.3390/min10020160 VL - 10 IS - 2 SP - 160 J2 - Minerals LA - en SN - 2075-163X ST - XRD Identification of Ore Minerals during Cruises UR - https://www.mdpi.com/2075-163X/10/2/160 Y2 - 2021/03/30/07:29:51 ER - TY - JOUR TI - Trying a board game intervention on children with autism spectrum disorder in Macau: how do they react? AU - Lok, Ka Ieong AU - Chiang, Hsu-Min AU - Lin, Yueh-Hsien AU - Jiang, Chunlian T2 - International Journal of Developmental Disabilities AB - Limited special education and related services are available for children with autism spectrum disorder (ASD) in Macau, especially those who are educated in general education classrooms. No intervention study has been conducted on these children. This study was conducted to explore the relationship between a board game play intervention and board game play behaviors and social communication of children with ASD educated in general education classrooms in Macau. A repeated measures design was used and the results of this study showed the mean occurrence of unprompted board game play behaviors per session during intervention was not significantly different from that during pre- or post-intervention. The mean occurrence of social communication per session during intervention was significantly higher than that during pre- and post-intervention. These findings suggest a positive relationship existed between the board game intervention used in this study and social communication of children with ASD. DA - 2022/07/12/ PY - 2022 DO - 10.1080/20473869.2022.2095861 DP - Taylor and Francis+NEJM VL - 0 IS - 0 SP - 1 EP - 9 SN - 2047-3869 ST - Trying a board game intervention on children with autism spectrum disorder in Macau UR - https://doi.org/10.1080/20473869.2022.2095861 Y2 - 2023/04/11/13:38:07 KW - Autism Spectrum Disorder KW - Macau KW - board game KW - play KW - social communication ER - TY - JOUR TI - Hydrothermal remobilization of subseafloor sulfide mineralization along mid-ocean ridges contributes to the global oceanic zinc isotopic mass balance AU - Liao, Shili AU - Tao, Chunhui AU - Wen, Hanjie AU - Yang, Weifang AU - Liu, Jia AU - Jamieson, John W. AU - Dias, Ágata Alveirinho AU - Zhu, Chuanwei AU - Liang, Jin AU - Li, Wei AU - Ding, Teng AU - Li, Xiaohu AU - Zhang, Huichao T2 - Geochimica et Cosmochimica Acta AB - Hydrothermal activity on mid-ocean ridges is an important mechanism for the delivery of Zn from the mantle to the surface environment. Zinc isotopic fractionation during hydrothermal activity is mainly controlled by the precipitation of Zn-bearing sulfide minerals, in which isotopically light Zn is preferentially retained in solid phases rather than in solution during mineral precipitation. Thus, seafloor hydrothermal activity is expected to supply isotopically heavy Zn to the ocean. Here, we studied sulfide-rich samples from the Duanqiao-1 hydrothermal field, located on the Southwest Indian Ridge. We report that, at the hand-specimen scale, late-stage conduit sulfide material has lower δ66Zn values (−0.05 ± 0.15 ‰; n = 19) than early-stage material (+0.13 ± 0.15 ‰; n = 10). These lower values correlate with enrichments in Pb, As, Cd, and Ag, and elevated δ34S values. We attribute the low δ66Zn values to the remobilization of earlier sub-seafloor Zn-rich mineralization. Based on endmember mass balance calculations, and an assumption of a fractionation factor (αZnS-Sol.) of about 0.9997 between sphalerite and its parent solution, the remobilized Zn was found consist of about 1/3 to 2/3 of the total Zn in the fluid that formed the conduit samples. Our study suggests that late-stage subsurface hydrothermal remobilization may release isotopically-light Zn to the ocean, and that this process may be common along mid-ocean ridges, thus increasing the size of the previously identified isotopically light Zn sink in the ocean. DA - 2022/10/15/ PY - 2022 DO - 10.1016/j.gca.2022.08.022 DP - ScienceDirect VL - 335 SP - 56 EP - 67 J2 - Geochimica et Cosmochimica Acta LA - en SN - 0016-7037 UR - https://www.sciencedirect.com/science/article/pii/S0016703722004410 Y2 - 2022/09/21/13:41:02 KW - Hydrothermal activity KW - Mid ocean ridge KW - Subsurface remobilization KW - Zinc isotopic mass balance ER - TY - JOUR TI - Trace-element compositions of sulfides from inactive Tianzuo hydrothermal field, Southwest Indian Ridge: Implications for ultramafic rocks hosting mineralization AU - Ding, Teng AU - Wang, Jia AU - Tao, Chunhui AU - Dias, Ágata Alveirinho AU - Liang, Jin AU - Wang, Yuan AU - Chen, Jie AU - Wu, Bin AU - Huang, Hui T2 - Ore Geology Reviews AB - The recently explored inactive Tianzuo hydrothermal field, in the amagmatic segment of the ultraslow-spreading Southwest Indian Ridge (SWIR), is closely associated with detachment faults. In this site, sulfide minerals are hosted by serpentine-bearing ultramafic rocks and include high-temperature (isocubanite, sphalerite, and minor pyrrhotite) and low-temperature (pyrite I, marcasite, pyrite II, and covellite) phases. In this study, trace-element concentrations of isocubanite and pyrite II were used to elucidate mineralization processes in ultramafic rocks hosting sulfides. Results show that isocubanite is enriched in metals such as Cu, Co, Sn, Te, Zn, Se, Pb, Bi, Cd, Ag, In, and Mn, and pyrite II is enriched in Mo and Tl. The marked enrichment in Te, Cu, Co, and In in isocubanite (compared with Se, Zn, Ni, and Sn, respectively) is most likely due to the contribution of magmatic fluids from gabbroic intrusions beneath the hydrothermal field. The intrusion of gabbroic magmas would have enhanced serpentinization reactions and provided a relatively oxidizing environment through the dissolution of anhydrite precipitated previously in the reaction zone, within high temperature and low pH conditions. This might have facilitated the extraction of metals by initial hydrothermal fluids, leading to the general enrichment of most metals in isocubanite. Metals in pyrite II have compositions similar to those of isocubanite, except for strong depletion in magmatically derived Te, Cu, Co, and In. This means that serpentinization processes had a dominating role in pyrite II precipitation as well. The enrichment of pyrite II in Mo and Tl is also indicative of seawater contribution in its composition. The study concludes that serpentinization reactions contribute effectively both to high- and low-temperature sulfide mineralization at Tianzuo hydrothermal field, with gabbroic intrusions further promoting high-temperature sulfide mineralization, providing additional metals, fluids and heat. In contrast, low-temperature sulfide mineralization occurred during the cooling of gabbroic intrusions, with decreasing rates of serpentinization reactions and a significant influence of seawater. DA - 2022/01/01/ PY - 2022 DO - 10.1016/j.oregeorev.2021.104421 DP - ScienceDirect VL - 140 SP - 104421 J2 - Ore Geology Reviews LA - en SN - 0169-1368 ST - Trace-element compositions of sulfides from inactive Tianzuo hydrothermal field, Southwest Indian Ridge UR - https://www.sciencedirect.com/science/article/pii/S0169136821004479 Y2 - 2022/09/21/13:41:17 KW - SWIR KW - Serpentinization KW - Sulfide KW - Tianzuo KW - Trace-element KW - Ultramafic rocks ER - TY - JOUR TI - Serpentinization and its implications for ultramafic-hosted sulfide mineralization: A case study at the Tianzuo hydrothermal field, 63.5°E, Southwest Indian Ridge AU - Ding, Teng AU - Dias, Ágata Alveirinho AU - Wang, Jia AU - Tan, Tingting AU - Liang, Jin AU - Wu, Bin AU - Tao, Chunhui T2 - Marine Geology AB - Reaction of ultramafic rocks with seawater and subsequent serpentinization has been considered one of the most important factors controlling the formation of ultramafic-hosted seafloor massive sulfide (UM-SMS) deposits. However, the mineralization processes responsible for these deposits remain poorly understood, in particular because they are less abundant as compared with their basaltic counterparts. In this work, serpentinites with different alteration grades collected at the Tianzuo hydrothermal field (THF), Southwest Indian Ridge, were studied. Mineralogical and chemical analyses were performed in the secondary opaque minerals resulting from serpentinization to understand the role of this process during the formation of UM-SMS deposits. Our results show that these opaque minerals mainly consist of magnetite, hematite, pentlandite, and minor pyrite, suggestive of high but varying oxygen and sulfur fugacities. The hematite is characterized by an enrichment in Mg, Si, Ni, and Co as compared with magnetite. Pentlandite associated with hematite has elevated and consistent Ni contents as compared with that associated with magnetite. These results indicate that breakdown and decomposition of primary silicate and sulfide minerals during serpentinization has controlled the sources of ore-forming materials. Concentrations of Te are variable and show a positive correlation with Ni in pentlandite associated with magnetite or hematite, suggesting that gabbroic intrusions provided additional material to the hydrothermal system. Oxidation and sulfidation conditions are ideal for the formation of trisulfur ion S3− in THF, which can significantly improve the capability of hydrothermal fluids for leaching ore-forming metals from the wall rocks, promoting the formation of THF. In addition of reduced systems, hydrothermal fluids with high oxygen and sulfur fugacities triggered by extensive seawater infiltration can most likely also develop in ultramafic-hosted systems. These results suggest that the areas with well-developed fractures are promising candidates for further exploration of UM-SMS deposits along mid-oceanic ridges. DA - 2023/01/01/ PY - 2023 DO - 10.1016/j.margeo.2022.106969 DP - ScienceDirect VL - 455 SP - 106969 J2 - Marine Geology LA - en SN - 0025-3227 ST - Serpentinization and its implications for ultramafic-hosted sulfide mineralization UR - https://www.sciencedirect.com/science/article/pii/S0025322722002407 Y2 - 2022/12/25/11:11:31 KW - Opaque minerals KW - Oxidation and sulfidation KW - Sulfide mineralization KW - Tianzuo hydrothermal field KW - Ultramafic rocks ER - TY - CONF TI - Ore-Forming Process of the Menez Gwen Hydrothermal Field: In situ S Isotopes and Trace Metals Constraints AU - Dias, Ágata AU - Qiu, Wenhong AU - Costa, Isabel Maria Amaral AU - Barriga, Fernando J A S T2 - Goldschmidt2020 C3 - Goldschmidt Abstracts DA - 2020/// PY - 2020 DO - 10.46427/gold2020.2143 DP - DOI.org (Crossref) SP - 2143 EP - 2143 LA - en PB - Geochemical Society ST - Ore-Forming Process of the Menez Gwen Hydrothermal Field UR - https://goldschmidtabstracts.info/abstracts/abstractView?doi=10.46427/gold2020.2143 Y2 - 2021/03/30/07:36:55 ER - TY - CONF TI - Sub-Seafloor Sulfide Mineralization in the Saldanha Hydrothermal Field, Mid-Atlantic Ridge (MAR) AU - Dias, Ágata AU - Qiu, Wenhong AU - Barriga, Fernando J A S AU - Tao, Chunhui T2 - Goldschmidt2020 C3 - Goldschmidt Abstracts DA - 2020/// PY - 2020 DO - 10.46427/gold2020.44 DP - DOI.org (Crossref) SP - 44 EP - 44 LA - en PB - Geochemical Society UR - https://goldschmidtabstracts.info/abstracts/abstractView?doi=10.46427/gold2020.44 Y2 - 2021/03/30/07:36:23 ER - TY - JOUR TI - Sulfur isotopic compositions of sulfides along the Southwest Indian Ridge: implications for mineralization in ultramafic rocks AU - Dias, Ágata AU - Ding, Teng AU - Tao, Chunhui AU - Liang, Jin AU - Chen, Jie AU - Wu, Bin AU - Ma, Dongsheng AU - Zhang, Rongqing AU - Wang, Jia AU - Liao, Shili AU - Wang, Yuan AU - Yang, Weifang AU - Liu, Jia AU - Li, Wei AU - Zhang, Guoyin AU - Huang, Hui T2 - Mineralium Deposita DA - 2020/10/31/ PY - 2020 DO - 10.1007/s00126-020-01025-0 DP - DOI.org (Crossref) J2 - Miner Deposita LA - en SN - 0026-4598, 1432-1866 ST - Sulfur isotopic compositions of sulfides along the Southwest Indian Ridge UR - http://link.springer.com/10.1007/s00126-020-01025-0 Y2 - 2021/03/30/07:28:44 ER - TY - CONF TI - Oxyhydroxide Hydrothermal Crusts from Saldanha Hydrothermal Field AU - Costa, Pedro AU - Dias, Ágata T2 - Goldschmidt2020 C3 - Goldschmidt Abstracts DA - 2020/// PY - 2020 DO - 10.46427/gold2020.478 DP - DOI.org (Crossref) SP - 478 EP - 478 LA - en PB - Geochemical Society UR - https://goldschmidtabstracts.info/abstracts/abstractView?doi=10.46427/gold2020.478 Y2 - 2021/03/30/07:37:17 ER -